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Finding the Fourth Proportional to 86.85, 120.15 and 83.48

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Solution

The fourth proportional to 86.85, 120.15 and 83.48 is: 115.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.85 : 120.15 = 83.48 : x
  2. Step 2: Convert to fraction form
    86.85/120.15 = 83.48/x
  3. Step 3: Cross multiply
    86.85x = 120.15 × 83.48
  4. Step 4: Simplify right side
    86.85x = 10,029.52
  5. Step 5: Solve for x
    x = 10,029.52/86.85
  6. Step 6: Final answer
    x = 115.48

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.